Palandu
Allium cepa
Palandu (Allium cepa) is a plant used in Ayurveda. Allicin and thiosulfinates are rapidly absorbed but quickly metabolized to diallyl sulfides. S-allyl cysteine shows >90% oral bioavailability. Cooking reduces quercetin content by 20-30% but may improve digestibility.
| Botanical name | Allium cepa |
|---|---|
| Family | Amaryllidaceae · other entries in this family |
| Order | Asparagales |
| Taxon identifiers | GBIF 2857697 · Wikidata Q20875685 · NCBI Taxonomy 4679 |
Names and identification
| Language | Name |
|---|---|
| English | Palandu |
Ayurvedic pharmacology (Dravyaguna)
| Property | Value | Description |
|---|---|---|
| Rasa (Taste) | Madhura, Katu | Primary taste |
| Guna (Quality) | Guru, Snigdha | Physical quality |
| Virya (Potency) | Ushna | Heating/Cooling effect |
| Vipaka (Post-digestive) | Madhura | Post-digestive effect |
Dosage forms and preparation
Dosage Forms: Fresh juice (Swarasa), Capsule, Tablet, Soft gel (oil extract), Powder (dehydrated), Syrup, Ear drops, Poultice
Standard Dosage: 5-15 mL fresh onion juice daily; 500-1000 mg dried onion extract daily; 1-3 g dehydrated onion powder daily
Bioavailability: Quercetin from onion is among the most bioavailable dietary sources (~50-65% absorption) due to the presence of quercetin glucosides (especially quercetin-4’-glucoside) which are actively transported by SGLT1 in the small intestine. Allicin and thiosulfinates are rapidly absorbed but quickly metabolized to diallyl sulfides. S-allyl cysteine shows >90% oral bioavailability. Cooking reduces quercetin content by 20-30% but may improve digestibility.
Optimal Timing: Fresh juice: morning on empty stomach or with meals. Supplements: with meals to reduce GI irritation and improve quercetin absorption with dietary fat. Ear drops: as directed by practitioner.
Standardized Extract: Standardized onion extract with quercetin >8% (as quercetin glucosides), total thiosulfinates >1%. Dehydrated onion powder retaining >70% of fresh quercetin content.
Shelf Life: Fresh juice: 4-8 hours unpreserved; Dehydrated powder: 12-18 months; Standardized extract: 24 months; Capsules: 24 months; Freeze-dried powder: 24-36 months
Storage: Fresh onion juice: refrigerated 2-8 deg C, use immediately. Dried forms: below 25 deg C, RH <40%, moisture-barrier packaging. Protect from light (quercetin photodegradation). Enteric-coated products in blister packs to prevent moisture ingress.
Marker Compounds: Quercetin, Quercetin-4’-glucoside, Quercetin-3,4’-diglucoside, Allicin, S-allyl cysteine, Diallyl disulfide, Kaempferol, Isorhamnetin
Extraction Methods
- Fresh mechanical juice extraction
- Aqueous extraction followed by spray drying
- Hydroalcoholic extraction (30-50% ethanol) for quercetin-rich fractions
- Steam distillation for volatile sulfur compounds
- Freeze-drying of juice for maximum bioactive retention
- Enzymatic extraction for enhanced yield
Synergistic Combinations
Published research
Literature indexed in PubMed that concerns this subject, grouped by study type. A paper appearing here is a record of what has been published, not evidence that the subject works, and laboratory or animal results do not transfer to people. Study titles link to PubMed so you can read the source rather than take our word.
Systematic reviews and meta-analyses1
- 2019. Traditional and modern uses of onion bulb (Allium cepa L.): a systematic reviewCritical reviews in food science and nutrition. PMID 30040448 · doi:10.1080/10408398.2018.1499074
Other clinical studies and reviews5
- 2023. Conservation and Global Distribution of Onion (Allium cepa L.) Germplasm for Agricultural SustainabilityPlants (Basel, Switzerland). PMID 37765458 · doi:10.3390/plants12183294
- 2022. Allium cepa: A Treasure of Bioactive Phytochemicals with Prospective Health BenefitsEvidence-based complementary and alternative medicine : eCAM. PMID 35087593 · doi:10.1155/2022/4586318
- 2021. Pharmacological Properties of Allium cepa, Preclinical and Clinical Evidences; A ReviewIranian journal of pharmaceutical research : IJPR. PMID 34567150 · doi:10.22037/ijpr.2020.112781.13946
- 2021. Onion (Allium cepa) and its Main Constituents as Antidotes or Protective Agents against Natural or Chemical Toxicities: A Comprehensive ReviewIranian journal of pharmaceutical research : IJPR. PMID 34400937 · doi:10.22037/ijpr.2020.112773.13940
- 2015. Onion: nature protection against physiological threatsCritical reviews in food science and nutrition. PMID 24915405 · doi:10.1080/10408398.2011.646364
Laboratory and animal studies6
- 2024. Purification and Characterization of α-Mannosidase from Onion, Allium cepaJournal of applied glycoscience. PMID 38799414 · doi:10.5458/jag.jag.JAG-2023_0010
- 2023. Antimicrobial Efficacy of Allium cepa and Zingiber officinale Against the Milk-Borne Pathogen Listeria monocytogenesJournal of microbiology (Seoul, Korea). PMID 38048022 · doi:10.1007/s12275-023-00086-w
- 2020. Screening and Assessment of Potential Plant Growth-promoting Bacteria Associated with Allium cepa LinnMicrobes and environments. PMID 32147605 · doi:10.1264/jsme2.ME19147
- 2017. Hydropower reservoirs: cytotoxic and genotoxic assessment using the Allium cepa root modelEnvironmental science and pollution research international. PMID 28213707 · doi:10.1007/s11356-017-8509-4
- 2003. Cloning and regiospecificity studies of two flavonoid glucosyltransferases from Allium cepaPhytochemistry. PMID 14568073 · doi:10.1016/s0031-9422(03)00507-7
- 1993. Interspecific hybrid between Allium cepa and Allium sativumTAG. Theoretical and applied genetics. Theoretische und angewandte Genetik. PMID 24196147 · doi:10.1007/BF00215036
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